Perovskites beyond photovoltaics: field emission from morphology-tailored nanostructured methylammonium lead triiodide

Abstract

Herein, methylammonium lead triiodide (CH₃NH₃PbI₃) nanorods and nanocrystals were prepared by a facile room-temperature wet chemical method via simple variation of the synthesis parameters. Proper phase formation was confirmed by X-ray diffraction studies, whereas the morphological features were investigated using field emission scanning electron microscopy and transmission electron microscopy. The bonding information and the presence of organic functional groups within the synthesized nanostructures were confirmed using Fourier transform infrared spectroscopy. The work function of the material was calculated using first principles studies. In an attempt to explore the potential of the perovskites beyond photovoltaic applications, the field emission performance of the nanostructured CH₃NH₃PbI₃ was investigated. The turn-on field (electric field corresponding to a 10 μA cm⁻² current density) was obtained as 4.2 V μm⁻¹ with the current density reaching up to 96 μA cm⁻² for an inter-electrode spacing of 200 μm for the nanorod samples. The emission current stability was tested to be good enough for as long as 2 hours. Finally, finite element-based simulations were performed using ANSYS to obtain a theoretical perception of our experimental findings.